PULLING JUST ENOUGH FROM GRAIN
Dearest Beerpeople,
As we’ve discussed before, the “first” step of brewing (after recipe development, grain milling, water heating, etc.) is the mash, wherein water meets grain, and the enzymes in the malt get to work converting starches to sugars, which the yeast can then eat. For beers like simple IPAs and Pilsners, you might mash in a single type of (pale) grain, but for most modern commercial beers, you’re dealing with a few to a lot of malts, and possibly some unmalted adjuncts.
And since some of those darker malts have already had their starches converted to sugars, a question naturally arises: do I need to add them at the beginning of the mash? Could I toss them in at the end, for whatever reason, or do something else with them entirely? And the answer, which is clear to anyone who has brewed a not-strictly-pale extract batch (see below), is absolutely.
Let’s talk about those options, then, and how each might be used by pros and hobbyists alike.
The Impetus: Homebrewing
The idea of adding grain at different parts in the mash is surprisingly quite old, dating roughly to the time of the first Porters (so, mid-18th century, I think? It’s times like these that make having all of my beer books in storage a real bummer), and tied to a technique called Parti-gyling, in which one lot of malt was mashed a few times over to produce worts of different strengths, which were either blended or fermented as distinct beers.
As far as I can tell, though, this practice died out with the death in large part of the parti-gyle, and I can’t think of a single recipe or reference to the practice of staggered malt additions through, oh, the middle of the 20th century or something like that.
However, the need to steep flavorful and starch-less, or at least enzyme-less, malt arose with the reemergence of homebrewing in the 70s and 80s. This is because, as an alternative to acquiring all of the malted and milled (not quite ground) barley required to brew beer, one could simply buy malt powder (dry malt extract or “DME”), or malt syrup (“LME”), for the bulk of their malt bill, and simply add in the darker malts...somehow. (I suspect this practice exploded in popularity due to the lack of widespread availability of physical malt in those early days.)
Instead of, say, mashing just those dark grains, which could be as little as a pound of malt (a third of what I use to brew a gallon of beer, for reference), those early homebrewers started a practice that is far and away the most common for extract brewers today: they tied up the color malts in muslin bags, and steeped them in the malt extract-enriched water for a set amount of time, say, 60 minutes or so. This was easy, and I’d assume way more reliable than conducting tiny mashes each time they want to use color malts (and I speak from experience here!)
While this certainly works, homebrewers are pretty restless tinkerers, and so over the years alternatives have been proposed, including steeping in cold water, and even adding the color grains to the boil directly (which, hey, is certainly faster). Fortunately, these options have been evaluated semi-empirically in articles over the last few years.
First, though, let’s talk briefly about the science of solubility and aroma.
A Technical Detour
While malted barley, “base malt,” contains starches and enzymes that convert in the mash into simple sugars, color malts contain some combination of melanoidins and simple and complex sugars, and generally zero enzymes, making the enzymatic process of mashing irrelevant. However, we wish to extract their sugars and their flavors and aromas, eventually working these into our (water-based) wort, and so it behooves us to discuss the effects of water temperatures on the extraction of these niceties (I’ll be brief!).
As concerns the sugar element, I have a fun anecdote for you. I worked at a cocktail bar in NYC a few years back, and as barback, it was my duty to prepare the syrups, which were based on a simple syrup recipe of one-to-one by weight of white cane sugar and fine NYC tap water (I say that unironically; it’s incredible tap water). While I had thought that you needed to use at least fairly warm water to melt the sugar, I was taught a startling alternative - as it turns out, you can use a blender and room-temp water to make simple. There are a few reasons for this (the high degree of turbulence means that the concentration of syrup around sugar granules is minimized, and the blender should maximize the surface area of the sugar, etc.), but the key principle is that the solubility of sugar in water, while obviously increasing with temperature, is pretty high even near freezing. While true for sucrose, it’s natural to assume that it’s true also for at least the simpler malt-based sugars.
Then, there are the aromas. I’ll spare you the lengthy distillation analogy (it’s an exact fit, mind you!), but the gist is that aroma compounds reach your nose by evaporating from their source (say, the skin of a peach, or a bruised mint leaf), which implies two things: there’s a finite number of aroma compounds in things like color malts, and the rate at which those compounds bleed off of their source determine the longevity, and perhaps potency, of scent. As it turns out, generally speaking, the “vapor pressure” of a wide array of compounds increases with temperature (the mathematical term for that is a “monotonic” relationship, fun fact), so by keeping aromatic things cooler, during extraction, say, we may be able to make more flavorful or aromatic beer.
The Practical Implications
Thus, you might expect that cold is good and hot is bad as far as extraction goes, and there are certainly schools of thought that would defend that, but there are people who love the hot steep as well. In doing research for this article, I found three semi-conflicting posts, so I’ll simply present their positions and leave you to decide who to trust (and for the record, after reading them, I lean towards a steep in hot wort, i.e. the original method)
Mary Anne Gruber at Briess evidently popularized the cold steep process, particularly for the darkest of grains, and the benefit of the method (beyond the hope of a subtler and more aromatic extract) is the ability to dial in the color of your beer by adding some variable amount of this extract. That sounds somewhat wasteful, granted, as a regular practice, but sounds great for recipe development.
The fine folks at Brulosophy, in a pseudo-experiment concerning cold steeping vs. full mashing (so no hot steep), found both a statistically significant difference in the beers (using a triangle test and 23 tasters), as well as, on behalf of the author, a slight subjective edge for the cold-steeped malt.
Finally, this great BYO piece that I swear I’ve referenced before covered all of the options you might consider, and declared a subjective edge to hot wort-steeped malt over all other methods, while revealing boiling the color grains to be a particularly bad idea.
That’s all fine and good, but are the pros actually doing this?
I have no sources for you, but there is a trick that I’ve been hearing about, and that we in fact employ in making our extraordinary Nightfall over Prague, namely adding the darkest malts (in this case, I think Carafa II or III, which is along the lines of a Roast Barley). In reviewing the recipe for that the other day, I was stunned to discover that it used one of those malts for 8% of the grain bill, which is the exact amount I’d used in a homebrewed Schwarzbier recipe that was way over the top in its chocolate character, so, while hardly scientific, I’m anecdotally suspicious that there’s something to this whole steeping thing.
Conclusion
We are officially in the weeds of brewing minutiae, but one thing that I enjoy about these farther reaches is that ultimately, brewing and homebrewing borrow a lot from science, both in its (often imperfect) emulation of the scientific method, as well as the usefulness of relying on established chemistry and physics, both simple and complex, in discovering and evaluating new brewing practices. If you hung on for dear life during this wild bull ride, congrats and thanks!
Cheers,
Adrian “Nye” Febre